Title Search for the Decay K_L ??? ??^0\nu\bar{\nu} at the J-PARC KOTO Experiment Author(s) Nakagiri, Kota Publication Singapore, Springer Singapore, 2020. Description XVI, 151 p. 121 illus., 109 illus. in color : online resource Abstract Note This book reports on a new result from the KL?????0???? search at the J-PARC KOTO experiment, which sets an upper limit of 3??10-9 for the branching fraction of the decay at the 90% confidence level, improving the previous best limit by an order of magnitude. To explain the matter???antimatter asymmetry in the universe, still unknown new physics beyond the standard model (SM) that breaks CP symmetry is necessary. The rare decay of a long-lived neutral K meson, KL?????0????, is a CP-violating decay. It is an excellent probe to search for new physics because new physics can contribute to the decay and change its branching fraction, while the SM is as small as 3??10-11. However, it is extremely difficult to search for because all of the decay products are neutral and two neutrinos are undetectable. The KL?????0???? signal is identified by measuring two photons from a ??0 with a calorimeter and confirming the absence of any other detectable particles with hermetic veto counters. The book contributes to the analysis of neutron-induced backgrounds which were the dominant background sources in the search. For the background caused by two consecutive hadronic showers in the calorimeter due to a neutron, the author evaluated the background yield using a data-driven approach. For another background caused by an ?? meson production????? decays two photons???by a neutron that hits a veto counter near the calorimeter, the author developed an original analysis technique to reduce it. The book also contributes to the analysis of the normalization modes (KL???3??0, KL???2??0, KL???2??) to measure KL yield, the estimation of the signal acceptance based on a simulation, and the evaluation of the trigger efficiency. As a result, significant improvements in the measurement were achieved, and this is an important step in the continuing higher sensitivity search, which can reach new physics with the energy scales up to O(100-1000 TeV) ISBN,Price 9789811564222 Keyword(s) 1. EBOOK 2. EBOOK - SPRINGER 3. Elementary particles (Physics) 4. Elementary Particles, Quantum Field Theory 5. Heavy ions 6. NUCLEAR PHYSICS 7. Nuclear Physics, Heavy Ions, Hadrons 8. Particle acceleration 9. Particle Acceleration and Detection, Beam Physics 10. QUANTUM FIELD THEORY Item Type eBook Multi-Media Links Please Click here for eBook Circulation Data Accession#   Call# Status Issued To Return Due On Physical Location I09118     On Shelf